Nov
14
2020

Why We See More Food Allergies

A recent review in a BBC article explained why we see more food allergies. It is important to note that one of the more important food allergies are peanut allergies. Certainly, they have risen from 1 in 250 children in 1997 to 1 in 70 children in 2008.

By all means, allergies come in various degrees of severity; an anaphylactic reaction is the most severe form. Notably, in England there was a rise of hospital admissions for anaphylaxis from 1,015 in 2013 to 1746 in 2019. This is a 72% increase in 6 years!

Theories why there may be more food allergies now

There are a number of theories why food allergies have been on the rise. There is a consensus now that the right composition of the gut bacteria is important for normal immune reactions to take place.

Hygiene theory

David Strachan proposed the hygiene theory of allergies in 1989. Briefly, his observation was that children of larger families were less likely to develop allergies. He interpreted this to mean that infections among siblings stabilized the immune system. In the meantime, it has become obvious that the gut plays an important role for the immune system.

Graham Rook’s “old friends” theory

Graham Rook’s “old friends” theory came out in 2003. This theory states that friendly microbes in the environment are mixing with the gut flora. This trains the immune system to balance.

Gut bacteria theory

There is good evidence that the more a child is given antibiotics as a child, the more likely it is that the person develops a food allergy later. The mechanism seems to go via the gut flora. In a way this is the other coin of Graham Rook’s “old friends” theory. If you kill the “good friends” bacteria in the gut by antibiotics, the immune system strikes back with allergic reactions.

Dual-allergen exposure

By exposing the child at 4 to 11 months to peanuts or peanut butter, the immune system develops tolerance to the peanut protein (LEAP=learning early about peanut). A study showed that by doing this 80% of 5-year and older children and adults do not have a peanut allergy.

Prenatal vitamin D and food allergies

A German study found that prenatal exposure to higher amounts of vitamin D resulted in a higher risk of developing food allergies before the age of two.

Use antibiotics only when necessary

Gut biome studies showed that the use of antibiotics can have long lasting effects on the composition of the gut flora. A patient in sepsis may require antibiotics. But when the patient has recovered it is important that the bowel flora is restored with probiotics. This balances the immune system and avoids allergic reactions.

Immunotherapy for food allergies

Allergists have long used desensitisation techniques to deal with inhalant allergies. Allergy shots every two or three weeks can be very helpful to suppress immune reactions to inhalants. The same technique works also for many food allergies. The allergist tests the patient’s skin on the forearm to see what positive reactions occur. Based on these findings an allergy serum is composed. A small amount is injected in intervals. The smallest amount is given first and the concentration is gradually increased until the maintenance dose is reached. This causes the immune system to produce competing antibodies that reduce the antibody-mediated reaction to the food allergies.

Why We See More Food Allergies

Why We See More Food Allergies

Conclusion

Food allergies are increasing in frequency and severity. There are several theories why food allergies develop. The most likely one is that friendly bacteria in the environment become part of the gut environment in the newborn. If we have the right composition of gut bacteria our immune system reacts normally. Administering antibiotics frequently and overcleaning our kitchens with too many cleaning agents affects our bowel flora negatively. This disbalance can cause allergic reactions. On the other hand, exposing a newborn between the age of 4 and 11 months to a variety of adult foods including peanut products will desensitize the child to peanut protein and prevent future allergies. Those who are severely affected by food allergies can see an allergist for allergy testing and consider desensitisation through allergy injections.

Jan
18
2020

Antibiotics In Children Can Trigger Allergies And Asthma Later In Life

Whoever treats a child’s cold must know that antibiotics in children can trigger allergies and asthma later in life. This is what a study released on Dec. 20, 2019 has shown. The researchers examined records of 798,426 children seen at the Department of Defense TRICARE health care program. They were born between 2001 and 2013. The physicians examined the children later again for allergies. The more antibiotics the children received in childhood, the more severe the youngster’s allergies were later in life.

More details about the study

The researchers found that different antibiotic types had different risks to cause allergic reactions later in life.

  • Penicillin: 1.3-fold risk
  • Penicillin with a β-lactamase inhibitor: 1.21-fold risk
  • Macrolides: 1.28-fold risk)
  • Cephalosporins: 1.19-fold risk
  • Sulfonamides: 1.06-fold risk

The type of allergies that the children developed later in life were food allergies, anaphylaxis, asthma, atopic dermatitis, allergic rhinitis, allergic conjunctivitis or contact dermatitis. The researchers stressed that their finding indicated an association between taking antibiotics and developing allergies later. It was not a causal relationship.

Food allergies in more detail

Anaphylaxis

This allergic condition is an emergency and requires immediate medical attention. It can occur when the body overreacts to peanuts or penicillin. It can occur with foods, and the reaction is sudden and severe. The symptoms may include wheezing, shortness of breath, a cough or tightness in the throat. The blood pressure may drop leading to light-headedness and passing out. The skin may show hives, swelling and a rash. The digestive symptoms may be nausea, vomiting and diarrhea. Other symptoms may involve itching eyes, headaches, anxiety and a feeling of impending doom.

Asthma

Airborne grass and tree pollens, mold spores and dust, but also peanuts and other strong allergens can trigger an asthma attack. The symptoms can be shortness of breath, wheezing, tightness in the chest, trouble falling asleep because of coughing and being short of breath.

Atopic dermatitis (eczema)

Often atopic dermatitis starts below the age of 5 and can last until late adolescence or adulthood. The symptoms can be dry skin, itching red patches of skin and thickened scaly skin. Allergic contact dermatitis is common in patients with atopic dermatitis.

Allergic rhinitis

People who suffer from allergic rhinitis are sensitized to particles in the air like grass and tree pollen, molds or cigarette fumes. They develop a stuffy nose, itching and watery eyes, sneezing and swelling around the eye lids. An allergist can do skin scratch tests to find out what the patient is allergic to. Subsequently, if the allergies are strong, the allergist may decide to start desensitization with allergy shots.

Allergic conjunctivitis

A person who is allergic to pollen and mold spores will react to this when in contact with it and often develop allergic conjunctivitis. An eye inflammation will develop within a few minutes leading to swelling of the conjunctiva around the eye ball. The eyes end up looking red, itching, burning and being watery.

Contact dermatitis

Contact dermatitis develops when your body brushes against a substance that your body has been previously sensitized to. One example is poison ivy contact dermatitis. But many other substances can cause similar reactions: solvents, shampoos, permanent wave solutions and rubbing alcohol. In addition, plants, bleach and detergents, fertilizers, pesticides and airborne substances (sawdust, dust from woollen materials) can also do the same.

The gut biome

Dr. Purvi Parikh is an allergist and immunologist at NYU Langone Health in New York. She was not involved in the study, but commented to it as follows: “One reason why there might be an association is because our microbiome, specifically in our gut, plays a large role in our immune systems. Antibiotics are known to not only kill the bacteria that are causing an infection, but also ‘good’ bacteria our immune system needs to protect us from developing allergic or autoimmune diseases.”

Treat bacterial infections with antibiotics when needed

She went on to say: “Overall, parents should know that this study shows an association but not necessarily cause and effect. So, if a child truly needs an antibiotic for a bacterial infection, they should not withhold it due to fear of allergic disease. However, on that same note, one should not over use antibiotics if not needed – for a virus or a cold – as there may be long-term consequences from over use.”

Antibiotics In Children Can Trigger Allergies And Asthma Later In Life

Antibiotics In Children Can Trigger Allergies And Asthma Later In Life

Conclusion

A new study showed that antibiotics can cause allergies and asthma later in life. The reason seems to be that our gut bacteria react to the antibiotics and the gut dysbiosis (disbalance of the gut bacteria) persists, when the antibiotics have been discontinued. The immune system can then react in ways that are detrimental to the child and adolescent. Anaphylaxis, asthma, atopic dermatitis, allergic rhinitis, allergic conjunctivitis or contact dermatitis are all different manifestations of allergies that can develop later in life. At this point we only know that there is an association between these allergic manifestations and the antibiotic use in childhood. More clinical trials will need to shed a light on what causes allergies in some children, but not in others.

Aug
31
2013

Peanut Allergies Are Deadly

In the US 1.5 million suffer from peanut allergies (Ref.1). People who have peanut allergies have to avoid peanuts and foods that contain even traces of peanuts lifelong. Here is a recent example of a 13-year old girl who died at a camp when she tried food contaminated with peanuts. Before we discuss peanut allergies in detail, we need to review first how the immune system is functioning.

How the immune system is primed to develop an allergy

Our immune system knows the difference between our own body components and substances that come from the outside. Scientists call this tolerance to our own surface proteins; and scientists call it an immune reaction that is mounting as a reaction to anything different from the surface antigens. There are different cells that make up the immune system. One of the main working cells of the immune system are the lymphocytes, with B cells originating from the bone marrow producing antibodies when an immune reaction occurs. Antibodies fit like a lock and key to the surface of an antigen, in this case the peanut protein. T helper cells are T lymphocytes (thymus derived lymphocytes) that help the B cells to recognize the difference between the own protein components and the outside components. There are also T killer cells, which get activated when parasites or viruses enter the body. With regard to peanut allergies it is the B cells and T helper cells that interact and the B cells produce a powerful, very specific IgE antibody directed against peanut protein. There are memory B cells, which continue to produce these specific anti-peanut protein antibodies and cause severe allergic reactions when future exposure to peanuts (even traces) occurs. So, the more often a person who is allergic to peanuts encounters even traces of peanuts, the immune system will get boosted and produce even more antibodies of the IgE type through reactivated B memory cells (Ref. 2). 98% of the population does not react to peanut exposure with allergies, but the other 2% who may have genetic susceptibility factors that predispose them to this often develop life-threatening reactions (an anaphylactic reaction).

What is an anaphylactic reaction to peanuts?

The most extreme form of allergies involving IgE antibodies can cause anaphylaxis. In the beginning stages of a peanut allergy there may only mild symptoms such as hives on the skin, itching and tingling around the mouth, a runny nose, a scratchy throat, wheezing, stomach cramps, vomiting or diarrhea. However, with a more severe allergy an asthma attack can develop, blood pressure drops leading to fainting or shock and severe airway obstruction in the throat or lungs can cause suffocation.

I vividly remember an 11-year-old boy who was brought in by ambulance to the emergency room of the hospital where I was working as the on-call physician. He had a hard time talking as his throat was swelling up as part of his anaphylactic reaction, within minutes he passed out completely (shock). Fortunately an anesthetist was in the department and could intubate him very quickly. However, despite adrenaline treatment, oxygen  by artificial ventilation and high doses of corticosteroid drugs he did not wake up until 10 hours later. In retrospect it turned out that he had eaten some crackers of a familiar brand that he knew as being free of peanut flour. However, he had seen an ad that the same brand of crackers was available as cheese crackers and he tried one of these, which prompted his admission to the hospital. The parents read the ingredients later: the label on the cheese crackers noted in small print that the flour of the cheese crackers contained peanut flour! Always read labels, even if it is a familiar brand! Fortunately for this boy he did not have brain damage from the time of his unconsciousness. He has been extremely careful since and is reading labels and avoiding unknown food items.

Peanut Allergies Are Deadly

Peanut Allergies Are Deadly

Cross-reactions between peanuts and other allergens

Allergies can be made worse when a person has inhalant allergies from pollens of trees or grasses that can share protein components from protein found in foods. The latest findings are that there are cross allergies between Fenugreek and lupine, which are both legumes, as are peanuts, so there are common antigens present in their proteins. A mouse-testing model has shed more light on this. Fenugreek has been shown to control mild diabetes by improving insulin resistance, but it cannot be consumed by persons who are highly allergic to peanuts because of the cross allergy mentioned.

There are other possible cross allergies to legumes like lentils, soy and chickpeas.

Other factors that can cause allergies to get worse

In the past the RAST test was often used.  This is a blood test for common food allergies that can cause severe allergic reactions like egg, milk, peanut, tree nuts, wheat, crustacean shellfish and soy. However, since about 2010 this has been replaced by the more sensitive ImmunoCAP Specific IgE test. Children who have food allergies to egg, milk, wheat, nuts, peanuts and soy often outgrow these allergies when they age, in other words their immune system can develop tolerance to many of these foods. Not so with peanut allergies ! They tend to be very persistent.

The immune responses to food allergies are complicated as there are immediate type immune reactions and delayed type immune reactions. The immediate immune responses are investigated with the above mentioned ImmunoCAP Specific IgE test. The delayed immune responses can be measured using the ELISA test. Positive IgE antibody tests for peanut protein are a marker that the person affected likely has more other allergies and they should be investigated by a knowledgeable allergist in that regard (Ref. 2).

What complicates the allergy sufferers’ lives even more is the fact that new wheat varieties since the 1970’s, called Clearfield wheat have a much higher gliadin (gluten) and lectin content than the old wheat varieties. As a result of exposure to this new type of wheat gluten intolerance and leaky gut syndrome have increased substantially in the world population (Ref.3). In addition, genetically modified foods like soy, corn, sugar beets, canola and others have challenged the immune system of sensitive humans even more. We do know that some people can develop autoimmune diseases from GMO foods and modern wheat, and this may be the reason that a host of diseases that belong into this disease category (MS, rheumatoid arthritis, Hashimoto’s thyroiditis, ankylosing spondylitis etc.) are much more common now than in the past. The geneticists who developed GMO foods seemed to be unaware how sensitive the immune system is, which will detect a few different amino acid sequences in a protein mounting a strong immune response to it.

Treatment for peanut allergies

The key for sufferers from peanut allergies is to avoid exposure to it. Read labels and use common sense. If something is not labeled, do not be tempted to eat it. Peanut flour is often mixed into the dough of crackers, not being labeled properly or only in fine print. With peanuts the antibodies usually circulate in the blood life long as the B memory cells do not diminish and get reactivated very quickly on repeat exposure producing antibodies again. As exposure to peanuts can cause severe asthma or anaphylactic shock, it is important to carry an EpiPen with you and to know how to use it.

In Europe attempts have been made to develop an oral desensitization method for food allergies including peanut allergies, but it has not produced concrete results yet. Recently, however, research from Texas, USA showed that it is possible to desensitize patients with peanut allergy by oral desensitization. In Australia where food allergies are more prevalent than in the US, tolerance to peanut, nut and shellfish allergies is being pursued by oral immunotherapy. Another group in Australia has developed a vaccination method using peptides, which are a sequence of amino acids, but shorter than the full peanut protein. It appears that this is the future direction of  treatment for peanut and other IgE mediated allergies: a kind of vaccination treatment to induce competing antibodies, which will neutralize the allergic IgE antibodies.

Conclusion

Peanut allergies have become more troublesome as the food industry has mixed peanut flour into Thai sauces, drinks, cookies, crackers and such. The person allergic to peanuts must read food labels and eat as much single-ingredient natural food as possible. This goes against the tendency of food processors who produce foods with a long rat tale of ingredients. If you see a label “may contain nuts or peanuts”, stay away from this product, as it is safer. Always carry an EpiPen or Twinject with you, just in case you develop an anaphylactic reaction (you only have a few minutes to stop the allergic reaction with adrenaline). In the future vaccination with a peanut protein specific peptide vaccine as mentioned regarding the Australian research, will probably become the treatment of choice.

More information on status asthmaticus (an acute asthma attack): http://nethealthbook.com/lung-disease/asthma-introduction/asthma-treatment/

References

1. Adkinson: Middleton’s Allergy: Principles and Practice, 7th ed. Chapter: Food Allergy. © 2008 Mosby.

2. Mandell: Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, 7th ed.© 2009 Churchill Livingstone.

3. William Davis, MD: “Wheat Belly Cookbook. 150 Recipes to Help You Lose the Wheat, Lose the Weight, and Find Your Path Back to Health”. HarperCollins Publishers LTD., Toronto, Canada, 2012.

Last edited Nov. 7, 2014

Apr
14
2013

Allergies Not Only In Spring

Springtime is the time of spring allergies: those affected develop a runny nose, itchy eyes and in more severe cases they may experience a flare-up of asthma. Allergies can be triggered by the increase of pollen counts in the air that occurs every spring. In those who are sensitive, this leads to antibody formation in the blood. But often people have not only sensitivities to the pollens of spring bloomers; they may also be allergic to spores from molds, to dust mites and may have underlying allergies to foods. The immune system has memory cells that memorize that a person has had an allergic encounter to one of these items in the past, and allergic reactions can become more significant with a future encounter. Allergies can also be made worse when a person has food sensitivities and there are cross reactions between pollens of trees or grasses that can share surface protein regions with similar protein regions in foods.

It is known that cross allergies are possible between birch pollen and apple, carrots or hazelnut. In its extreme form allergies due to antibodies, called IgE antibodies, can cause anaphylaxis. A person presensitized by inhaling birch pollen, after eating an apple, hazelnuts or a carrot can develop itching of the throat, swelling of the lips and very quickly deteriorate getting into an anaphylactic shock.

Other cross allergies exist between ragweed pollen, which is a powerful inhalant allergen and melons or bananas. Again there are specific IgE antibodies that are responsible for this immune reaction. In this case the ragweed allergy primes the immune system to produce IgE antibodies, which are potentiated by certain foods that share similar protein components as the ragweed pollen.

In the following I will deal with inhalant allergies separately from food allergies.

Allergies Not Only In Spring

Allergies Not Only In Spring

Inhalant allergies

Inhalant allergies are easier to diagnose and to treat than food allergies. Your doctor will likely refer you to an allergist when you have allergies that do not respond to treatment with intermittent over the counter antihistamines. Your symptoms may come on in the spring with itchy eyes and a runny nose. From year to year you find that you become more and more dependent on antihistamines and nose drops to unplug your nose. The allergist likely will do sensitivity tests, which consist of skin prick or scratch tests on the back or the forearms.

In more serious allergies, where the patient has coughing and wheezing attacks following allergic reactions, the allergist may suggest to start intermittent allergy injections alongside the standard inhalation therapy for asthma. An allergy serum is prescribed where the lab mixes ingredients based on all of the positive tests that led to a strongly positive skin reactions when allergy testing was done. Typically the family doctor or his nurse will start the allergy injections initially in weekly intervals, later when the maintenance dose is reached, it may be modified to injections every 10 to 14 days.

The allergy injections stimulate the immune system to produce harmless competing antibodies, which counteract the disease producing allergic antibodies. In the process of desensitization shots the immune system will normalize, which means that the inflammatory response of the immune system settles down to normal.

This is not the end of the story with inhalant allergies. The patient needs to be retested on a yearly basis by the allergist. The immune system changes all the time as new allergies can develop and old ones may go away.

Retesting is necessary to keep track of what is going on and to change the composition of the allergy serum. Those patients who are working together with the allergist can do very well, and often they gradually outgrow their allergies. Others may not be so lucky. They may have reactions to the allergy injections. In these cases avoidance of what causes the allergy may be the only solution to treat the allergies.

There is an alternative to allergy injections, which has been used in Europe, namely a sublingual immunotherapy. Recently there has been a review of the literature for FDA approval that is needed for oral desensitization for ragweed, dust mites, grass pollen and cat dander. It will take some time before the FDA approval process will become a reality for sublingual desensitization in the US.

A special form of inhalant allergies are allergies to pets (mainly dogs and cats, but also allergies to petting zoo animals). The dander that the human comes in contact with is a protein contained in the animal hair. It causes hives when it touches the skin. This occurs as the dander is absorbed through the skin and meets the local mast cells that release histamine. This in turn is responsible for the hive formation. Sneezing and even asthma can develop from inhaled protein particles that reach the lungs. Allergy injections for the treatment of animal dander allergies are very limited as they often do not help or make the allergies worse. Avoidance of animal contact is usually what the allergist recommends as the solution, a recommendation, which often is not appreciated by the affected animal lover.

Food allergies

Often we eat  some foods more frequently, because they are our favorites. This means that our gut lymphocytes that get in contact with these foods can start to react to one or more of the foods we ingest. At this time we may experience abdominal cramps, diarrhea, vomiting and a host of other possible symptoms.

The physician will tell the patient that testing for food allergies is a problem as most of the usual skin tests employed for inhalant allergies do not reliably work in determining food allergies. The doctor will ask the patient or the mother of the child with food allergies to keep a food diary and keep track of the allergic symptoms in the diary as well. An elimination diet will have to be devised based on the information gathered in the diary as it becomes clear from that record which foods cause which symptoms. The foods causing allergic symptoms are subsequently eliminated. This is a cumbersome process, but it is the most reliable method of testing and treating food allergies.

In the past there was a blood tests, called RAST test, which tested for common food allergies that can cause severe allergic reactions like egg, milk, peanut, tree nuts, wheat, crustacean shellfish and soy. Since about 2010 this has been replaced by the more sensitive ImmunoCAP Specific IgE test.

Children often develop food allergies to egg, milk, wheat, nuts, peanuts and soy, which are food allergies with positive IgE tests. When they age, their immune system develops tolerance to many of these foods and they often outgrow these allergies.

There are other popular lab tests where a blood drop is analyzed with IgG, IgM and IgE antibodies against a panel of foods. A number of suppliers offer these tests.  However, the specificity, sensitivity and reliability can pose problems with regard to the interpretation of the results: allergists often point out that a test may be a false positive when a person likes certain foods and IgG antibodies against this food show up despite the patient having no symptoms. Another specialist may interpret this to indicate that the body shows early sensitization to a certain food, but clinically it is not yet obvious. In other words the sensitivity of the test is so high that it undermines the validity of the test. Recently a panel of international scientists reviewed the validity of these IgG based food intolerance tests and they found the tests not reliable.

The immune responses to food allergies are complicated as there are immediate type immune reactions and delayed type immune reactions. The immediate immune responses are investigated with the above mentioned ImmunoCAP Specific IgE test. The delayed immune responses can be measured using the ELISA test.

Other considerations about allergies

You see from this discussion that a patient with allergies needs a properly trained allergist who will do a comprehensive analysis involving a thorough history, examination, blood tests and immune tests.  The test results have to be interpreted with the experience and the clinical judgment of the specialist.

Since the 1970’s when Clearfield wheat was introduced around the world on a large scale, which has a much higher gliadin (gluten) content than the old wheat varieties. As a result of exposure to this new type of wheat gluten intolerance and leaky gut syndrome have increased substantially in the world population. Genetically modified foods like soy, corn, sugar beets, canola and more have challenged the immune system of sensitive humans even more to an extent, which is not fully understood yet. We do know that some people can develop autoimmune diseases and this may be the reason that a host of diseases that belong into this disease category (MS, rheumatoid arthritis, Hashimoto’s thyroiditis, ankylosing spondylitis etc.) are much more common now than in the past.

After food elimination for 2 to 12 months depending on the severity of the food allergy, your body may have eliminated the allergy to the food you have avoided, in other words your body built up tolerance. Before you expose yourself to any food that you used to be allergic to and that you want to re-test, it is best to have an EpiPen ready in case your allergy has not resolved. Caution is necessary with regard to foods that cause more severe allergies, e.g. shellfish or peanuts, which may last life long. It is safer to avoid these foods that cause more severe allergies altogether.

Allergic reactions of the immune system belong into the category of chronic inflammatory diseases. These are known to be the root of chronic diseases like asthma, arthritis, heart disease, high blood pressure and cancer. When you are vigilant about allergies and get proper assessment and treatment by an allergist, you will prevent serious health problems including the above mentioned chronic diseases.

More on asthma, which is a chronic inflammatory lung condition, often associated with multiple environmental allergies:

http://nethealthbook.com/lung-disease/asthma-introduction/

Last edited Nov. 6, 2014